Multiple-stage pressure-stage turbine



J. KARRER. MULTIPLE STAGE PRESSURE STAGE TURBINE. AFPUCATION FILED FEB. 19, 1920. 1,429,508. v Pa entedsept. 19, 1922.

2 SHEETS-SHEET I.

J. KARRER. MULTIPLE STAGE PRESSURE STAGE TURBINE. APPLICATION FILED FEB. 19' I920. 1 ,429 508, Patented Sept. 19, 1922 2 SHEETS-SHEET 2- JOSE KARRER, OF ZURICH, SWITZERLAND, ASSIGNOR TO MAS CI-IINENFABRIK OERLIKON, OF OERLIKON, NEAR ZURICH, SWITZERLAND, A CORPORATION OF SWITZERLAND.

MULTIPLE-STAGE PRESSDRE-STAGE TURBINE.

Application filed. February 19, 1920. Serial na-esasoi.

(GRANTED UNDER THE 'rRovIsmNs or THE ACT or MARCH 3, 1921, 41 STAT. 1313.)

To all whom it may concern:

Be it known that I, JOSEF KARRER, a citizen of the Swiss Republic, residing at Zurich, in the Republic of Switzerland, have invented certain new and useful Improvements in IvIultiple-Stage- Pressure-Stage Turbines (for which I-have filed applications in Switzerland, patented 16th September, 1919, numbered 82,31et; Great Britain, patented 23d June, 1921, numbered 138,597 Belgium,

patented th March, 1920, numbered 284,- 928; France, patented lath September, 1920, numbered 507,362; Germany, patented 16th February, 1921, numbered 332,959; Czecho- 15 Slovak Republic, patented 3d June, 1921,

numbered 5,336; Italy, patented 11th July, numbered 523.35), of which the following is a specification.

This invention relates to improvements in 20 multiple-stage pressure-stage turbines.

In multiple-stage pressure-stage turbines all the stages are calculated forlthe same quantity of steam, and these turblnes attain their highest efiiciency at full load, that is to 5 say with-the quantity of steam on which the calculation of the design was based. Under partial load the efiiciency diminishes because in consequence of the reduced quantity of steam, the conditions of flow no longer cor:

respond to the, design. Shutting off the steam ducts of the individual stages in accordance with the load has been found too difficult and expensive, especially because owing to the considerable distance separating the stages in consequence of the interposition of the regulating devices-the effluent velocity to the stages is lost, and the efliciency is thereby impaired. Consequently the practice has been adopted of regulating the first pressure stage only-which may, it-

self, consist of several velocity stages-and this type of construction is at present widely used,'especially in velocity-stage turbines. I

.Overload in steam turbines is generally met by supplying auxiliary live steam to the the heat-drop of the high-pressure stages not being utilized so far as the auxiliary steam is concerned. Consequently, the efficiency of the turbine sinks so much the more in proportlon as 1t 1s overloaded. In velocity-stage turbines, or 1n pressure-stage turbines with only a single high-pressure stage, it is, of course, possible to provide auxiliary ducts for the overload; and in such case the high-pressure heat drop is more or less satisfactorily utilized, Such turbines work advantageously, even with overload. It is also known that velocity-stages have a considerably lower efficiency than pressure stages in the ease of medium and large outputs. ."Nevertheless, velocityv stages are largely employed in high-pressure nowadays, the probable reason being their favourable behaviour in cases of overload; Byreason of'the high initial pressure, the use of only one high-pressurestage isgenerally disad vantageous, and therefore, in pressure-stage turbines,'the auxiliary live steam, in case of overload, is admitted'atthe end of the highpressure stages, utilization of the high-pressure heat drop being dispensed with.

The present invention enables the'steam to be favourably utilized at overload and par tial load, in the case of pressure-stage turbines as well. According to the invention, in a multiple stage pressure stage steam turbine, which is provided with auxiliary ducts in addition to the guide ducts, calculated for a particular quantity of steam, the steam introduced through the auxiliaryducts does not flow immediately from'the first stage or one of the first stages into the succeeding stage, but is first diverted outward (radially), and is then admitted centripetally to one of the subsequent stages. In this stage the heat drop can then be further utilized. Moreover one or more stages may. be passed over. Furthermore, a stop valve or the like, which is only opened in the event of an overload, maybe provided between two overload stages.

In the accompanying drawings, showing an embodiment of my invention, Fig. 1 is an axial section of the new multiple-stage pressure-stage turbine.

Fig. 2 is a section along the lines 22 of Fig. 1, the lower half of the'section of 2 being taken through the steam ad mission to the guide ducts.

Live steam is admitted from the main inlet valve to the regulating piston valve 1 (Fig. 2), where it is more or less throttled according to the load up to full load. The annular channel 2 does not supply the entire circumference; the nozzle chest 3 is calculated for the normal quantity of steam at full load. The steam passes through the partially supplied high pressure portion consisting of three stages, and reaches by way of the transition chamber 4, the fully supplied low pressure group of stages.

For guiding the overload steam, auxiliary channels are provided in the first and. third stages. They, however, are not supplied up to full load, the two valves 5 and (3 shutting off the admission of steam. As soon as the turbine is overloaded or as soon as the normal quantity of steam is not suiiicient to carry the desired load, the two overload valves open automatically. The regulating lever 7 bears, by means of the adjustable screw 8 against the relay piston 9, which becomes displaced downwardly so that the second overload valve 6 is entirely opened by oil under pressure. After the screw 8 abuts against thecasing of the relay piston, it. becomes the fulcrum of the regulating lever 7, and the first overload valve 5 be comes opened as far as is required against the opposition of the spring 10. The over load steam issuing from the annular channel 2 through the valve 5 reaches the inlet channel ll, from whence it passes by way of the nozzle chest 12 through the first rotor, and being diverted outwardly, passes through the open .second overload valve 6 to the auxiliary chest 13 in the third stage, and does useful work in the third rotor, and thereupon mixes in the annular space elwith the normal quantity of steam, to flow onwards through the low pressure portion. The overload steam works only in the first and third stages; the heat drop of the high pressure portion, however, is smaller with overload than with full load, inasmuch as the pressure in the transition space increases in accordance with the larger amount of steam. For this reason the high pressure heat drop of the auxiliary steam can be fully exploited in two stages.

The invention ensures economical running with overloads, and also enables increased economy to be obtained in the case of partial loads. This is effected by calculating the normal high-pressure ducts for a smaller quantity of steam than the low pressure stages, e. g. for per cent of the nominal normal output. The high-pressure aggregation operates most favourably with a (0 per cent load, and more favourably with all smaller loadsthan if the high-pressure stage were calculated for 100 per cent load. At full load the low-pressure aggregation operates at its best, and owing to the favourable method of distributing the auxiliary steam, the high-pressure aggregation still continues to work favourably, so that, with loads of 70l00 per cent, the steam consumption of the turbine is just as'satisfactory as in the usual types, and even better than these in the case of smaller loads. Machines constructed in this manner also work very favourably with overloads, if further overload ducts be introduced.

It is not essential that the auxiliary live steam should be supplied to the first stage; and the turbine may also consist of any desired number of stages and groups of stages, and of velocity stages and pressure stages; and, indeed, the invention can be applied to any type of construction. tion of the auxiliary valves may be effected by hand or automatically.

l/Vhat I claim as new and desire to secure by Letters Patent is 1. In a multi-stage pressure-stage turbine, a group of high-pressure stages, guide ducts of normal capacity partially supplying and permanently interconnecting said stages of said group, auxiliary guide ducts partially supplying a stage of said group, means for controlling the steam supplied by said auxiliary guide ducts to said stage, auxiliary guide ducts partially supplying a subse quent stage of said group, means for diverting steam from said firstanentioned stage to said auxiliary guide ducts of said subsequent stage and means for controlling the flow of Steam from said first-mentioned stage along said diverting means to said auxiliary guide ducts of said subsequent stage.

2. In a multi-stage pressure-stage turbine, a group of high-pressure stages, guide ducts of normal capacity partially supplying and permanently interconnecting said stages of said group, auxiliary guide ducts partially supplying an early stage of said. group, means for controlling the steam supplied by said auxiliary guide ducts to said early stage, auxiliary guide ducts partially supplying a remote subsequent stage of said group, means for diverting steam from said early stage past an intermediate stage to said auxiliary guide ducts of said remote subsequent stage and means for controlling the flow of steam from said early stage along said diverting means to said auxiliary guide ducts of said remote subse uent stage.

3. In a mu ti-stage pressure-stage turbine, a group of high-pressure stages, guide ducts of normal capacity partially supplying and permanently interconnecting said stages of said group, auxiliary guide ducts partially supplying the first stage of said group, means for controlling the steam supplied by said auxiliary guide ducts to said first stage, auxil1ary guide ducts partially supplying a remote subsequent stage of said group, means for diverting steam from said first stage past an intermediate stage to said auxiliary guide The operaducts of said remote subsequent stage and means for controlling the flow of steam from said first stage along said diverting means to said auxiliary guide ducts of said remote subsequent stage.

4. In a multi-stage pressure-stage turbine, a group of high-pressure stages, guide ducts of normal capacity partially supplying and permanently interconnecting said stages of said group, auxiliary guide ducts partially.

supplying a stage of said group, a valve controlling the steam supplied by said auxiliary guide ducts to said stage, auxiliary guide ducts partially supplying a subsequent stage of said group, a passage leading from said first-mentioned stageto said auxiliary guide ducts of said subsequent stage and a valve controlling the flow of steam from said first mentioned stage along said passage to said auxiliary guide ducts of said subsequent stage.

5. In a multi-stage pressure-stage turbine, a group of high-pressure stages, guide ducts of normal capacity partially supplying and permanently interconnecting said stages of said group, auxiliary guide ducts partially supplying an early stage of said group, a valve controlling the steam supplied by said auxiliary guide ducts to said early stage,

auxiliary guide ducts partially supplying a remote subsequent stage of said group, a passage leading from said early stage past an intermediate stage to said auxiliary guide ducts of said remote subsequent stage and a valve controlling the flow of steam from said early stage along said passage to said auxiliary guide ducts of said remote subsequent stage.

6. In a multi-stage pressure-stage turbine, a group of high-pressure stages, guide ducts of normal capacity partially supplying and permanently interconnecting said stages of said group, auxiliary guide ducts partially supplying the first stage of said group, a valve controlling the steam supplied by said auxiliary guide ducts to said first stage, auxiliary guide ducts partially supplying a remote subsequent stage of said group, a passage leading from said first stage past an intermediate stage to said auxiliary guide ducts of said remote subsequent stage and a valve controlling the flow of steam from said.

first stage along said passage to said auxiliary guide ducts of said remote subsequent stage.

In testimony whereof, I afiix my signature.

JOS-EF KARRER. 

